Evidence map›Paper›PMID 40394972›Full record

Trial reportNeurogastroenterology and motility2025

Changing Gastrointestinal Transit Time Alters Microbiome Composition and Bile Acid Metabolism: A Cross-Over Study in Healthy Volunteers.

Evette B M Hillman, Maximilian Baumgartner, Danielle Carson, Gregory C A Amos, Imad Wazir, Haider A Khan, Malik A Khan, Sjoerd Rijpkema, Julian R F Walters, Elizabeth M H Wellington and 2 more

Abstract readRandomized Controlled Trial
In one paragraph

Trial report in Neurogastroenterology and motility, 2025. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 2 papers.

0numbers the graph read from it
0cells of the map it votes in
2citing papers in PubMed
–field-weighted citation impact
1 · What the graph read from it

What it found

Each row is one number read from the abstract, on the scale the paper reported it, with its interval. Left of the dashed line favours the treatment, right favours the comparator. Under each row is the sentence it came from. New to these charts? A ten-minute tutorial.

The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.

2 · The registry

The trial behind it

Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.

Neither the registry nor the abstract names a trial number. If this is a trial report, that itself is worth knowing.

3 · Its place in the literature

Who cites it

2 citing papers in PubMed.

  1. Review
  2. Review
4 · The record

Corrections and comments

PubMed lists nothing against this paper. Absence here is not a guarantee, only a check that was made.

5 · Who and what money

Authors and funding

12 authors.

Evette B M HillmanDiagnostics, Medicines and Healthcare Products Regulatory Agency, London, UK.ORCID https://orcid.org/0000-0002-4896-4621
Maximilian BaumgartnerDivision of Gastroenterology and Hepatology, Medical University of Vienna, Vienna, Austria.
Danielle CarsonDiagnostics, Medicines and Healthcare Products Regulatory Agency, London, UK.
Gregory C A AmosDiagnostics, Medicines and Healthcare Products Regulatory Agency, London, UK.
Imad WazirDepartment of Gastroenterology, University Hospital Plymouth, Plymouth, UK.
Haider A KhanDepartment of Gastroenterology, University Hospital Plymouth, Plymouth, UK.
Malik A KhanDepartment of Gastroenterology, University Hospital Plymouth, Plymouth, UK.
Sjoerd RijpkemaDiagnostics, Medicines and Healthcare Products Regulatory Agency, London, UK.ORCID https://orcid.org/0000-0003-0389-8904
Julian R F WaltersDivision of Digestive Diseases, Imperial College London, London, UK.
Elizabeth M H WellingtonSchool of Life Sciences, The University of Warwick, Coventry, UK.
Ramesh ArasaradnamDepartment of Gastroenterology, University Hospitals Coventry & Warwickshire, Coventry, UK.
Stephen J LewisDepartment of Gastroenterology, University Hospital Plymouth, Plymouth, UK.

Funding

Department of Health and Social Care (DHSC) Policy Research Programme (NIBSC Regulatory Science Research Unit)
6 · The paper itself

Abstract

backgroundThe specific influence of whole gut transit time (WGTT) on microbiome dynamics and bile acid metabolism remains unclear, despite links between changes in WGTT and certain gastrointestinal disorders. Our investigation aimed to determine the impact of WGTT changes on the composition of the fecal microbiome and bile acid profile.

methodsHealthy volunteers (n = 18) received loperamide, to decrease bowel movement frequency, and senna, a laxative, each over a 6-day period, in a randomized sequence, with a minimum 16-day interval between each treatment. Stool samples were analyzed for microbiome by shotgun sequencing and bile acid composition determined with high-performance liquid chromatography coupled to tandem mass spectrometry. Sera were examined for markers of bile acid synthesis. KEY

resultsSenna or loperamide decreased or increased WGTT, respectively. Treatment altered stool characteristics, bowel movement frequency, and stool weight. The senna-treated group had increased primary and secondary fecal bile acids; serum levels of fibroblast growth factor 19 were significantly reduced. Increasing WGTT with loperamide led to an increase in bile salt hydrolase genes, along with elevated bacterial species richness (p = 0.04). Thirty-six species exhibiting significant differences were identified, several of which have notable implications for gut health. WGTT displayed negative correlations with total primary (particularly chenodeoxycholic acid) and secondary bile acids (ursodeoxycholic acid and glycochenodeoxycholic acid). Treatment-induced changes in microbiome composition and bile acid metabolism reverted back to baseline within 16 days.

conclusionWhole gut transit time changes significantly affect fecal microbiome composition and function, as well as bile acid composition and synthesis in healthy subjects. This consideration is likely to have long-term implications.

Indexed as

Bile Acids and SaltsGastrointestinal MicrobiomeGastrointestinal TransitAdultCross-Over StudiesFecesFemaleHealthy VolunteersHumansLaxativesLoperamideMaleMiddle AgedYoung AdultBile Acids and SaltsLaxativesLoperamidebile acids metabolismgastrointestinal homeostasisloperamide and senna treatmentmicrobiomewhole‐gut transit‐time (WGTT)

Identifiers

PMID40394972
PMCPMC12435802

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Registered trials

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Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.